Multiscale Analysis of Silicon Carbide-Chemical Vapor Deposition Process

Abstract

A kinetic study, which was performed by using multi-scale (a macro and a micro-scale) analysis, is presented in order to determine the reaction mechanism of the chemical vapor deposition (CVD) of silicon carbide (SiC) from CH3SiCl3 (MTS)/H2 gaseous mixture. The multi-scale analysis provides two well-defined reaction fields, corresponding to the flat substrates placed in a hot wall reactor and micro trenches on the substrate surface, with centimeter and submicron characteristic length scales, respectively. The microcavity method is a micro-scale analysis used to study the relative contributions of gas-phase and surface reactions to the SiC growth, and to determine the sticking probability of growth species in CVD reaction systems. From the macro-scale analysis, activation energy of the growth rate was estimated to be 43.0 kcal/mol at the up-stream part and the sticking probability was estimated to be 9.5 x 10(-7) at 1273 K and 6.8 x 10(-6) at 1373 K. On the other hand, we examined a sticking probability (eta) and the reaction mechanism by using the microcavity method. From the micro-scale analysis, we found that at least two growth species, a stable intermediate 1 (eta 1, = 1.3 x 10(-3) at 1273 K and 4.5 x 10(-3) at 1373 K) and a highly active intermediate 2 (eta 2 = 2.0 x 10(-1) at 1273 K and 5.4 x 10(-1) at 1373 K), are formed as byproducts of the gas-phase reaction. Activation energy of the sticking probability was 43.9 kcal/mol in the case of the intermediate 1 and 34.5 kcal/mol in the case of the intermediate 2. We could also confirm that the source precursor, MTS, was not the film growth species. Another analytical model based on Monte Carlo simulations correlates the film profile in the microcavity to the sticking probability of the deposition species. The combination of these two analysis techniques presents an overall picture of the reaction scheme.